Adjustable seat assemblies for motor vehicles typically provide for a seat to be moved or adjusted in a forward/rearward direction along a pair of spaced apart track assemblies. Each track assembly typically includes a first track member that is mounted to the vehicle and a second track member that is supported for movement relative to the first track member. The first and second track members are usually mounted in a horizontal configuration with bearing members located on sides of the first and second tracks. The seat is adjusted in the forward/rearward direction by sliding the second track members relative to the first track members. This is often referred to as a “two-way” adjustable seat. The adjustable seat assembly can also provide for the seat to be moved or adjusted in a upward/downward direction. The seat is usually adjusted in an upward/downward direction by raising/lowering the seat relative to the track assemblies. This is often referred to as a “four-way” adjustable seat. The adjustable seat assembly can additionally provide for the forward and rearward edges of the seat bottom to be moved or adjusted in an upward/downward direction independently of each other and/or provide for a seat back to be pivoted or adjusted in a forward/rearward direction relative to a seat bottom. These are often referred to as a “six-way” adjustable seat or an “eight-way” adjustable seat. Of course, any combination of the above-described seat adjustments can be utilized in particular adjustable motor vehicle seat.
A motor vehicle seat can have an occupant classification system (OCS) that senses weight to determine if a person is occupying the seat and, if so, the weight and consequently the size of the person occupying the seat. This information can be utilized so that a corresponding airbag is not triggered if the seat is unoccupied. Additionally, this information can be utilized so that the corresponding airbag is not triggered if the seat is occupied by a child or infant. Furthermore, this information can be utilized with corresponding airbags having variable filling volumes to adapt the filling volume to the size of the person occupying the seat and optimally restrain the person during an accident.
Typically, the OCS for an adjustable motor vehicle seat includes a plurality of weight sensing devices such as force sensors, stress or strain gauges, or the like mounted between the vertical lift assembly and the track members. A seatbelt is mounted to the vertical lift assembly so that the seatbelt is located above the weight sensing devices. Seatbelt loads travel down through the vertical lift assembly. During a crash, a vertical drive of the lift assembly can be subjected to as much as two times the force that it would experience in a standard design where the seatbelt is mounted to the track. As a result, at least the vertical drive, drive links and seat mounting brackets need to be considerably stronger to handle increased loads. Thus, a standard lift assembly cannot be utilized and a special lift assembly must be provided at added cost. Accordingly, there is a need in the art for an improved adjustable motor vehicle seat assembly having an occupant classification system.